The price of two grams of a strain of marijuana named 'Sweet Lafayette' is displayed at Top Shelf Cannabis in Bellingham, Washington. Photograph: Ted S Warren/AP

A few Washington stores are opening their doors on Tuesday to sell recreational marijuana, legally, for the first time in the state. The Evergreen State joins Colorado as the only US states that allows the sale and possession of recreational marijuana.

Washington authorities capped the number of possible retail stores at 334, but the stores remain blocked in some local jurisdictions.

The state has granted so few licenses because it is overwhelmed by the demand for the permits. More than 7,000 people applied for marijuana licenses, inundating the 18 licensing investigators tasked with with reviewing marijuana growing license applications.

How much does a legal gram cost?

While some stores have said they will sell a gram from $10 to $12 – comparable to prices at unregulated dispensaries in the state – others anticipate selling marijuana at $20 a gram or more because of the low supply and high taxes, which are 25% wholesale and 25% at retail.

Do you have to be a Washington resident to buy from licensed dispensaries?

No, but you do have to be 21 or older. If you meet that requirement, you can purchase up to an ounce of dried marijuana, up to 7g of concentrated marijuana (like hash) and up to 16oz of pot-infused treats (like edibles). Edibles, however, must be approved by the state and no stores have been granted that approval yet.

Where can people consume cannabis?

Public consumption isn’t allowed in Washington – so smoking or ingesting edibles is prohibited on streets, in parks or other public places. It is legal in people's homes, though apartment complexes and hotels can ban smoking, especially if the building already has anti-tobacco smoking laws. State authorities are considering legalizing the activity at specially created private-use clubs or other similar locations.

How did recreational marijuana become legal in Washington?

Washington residents voted in favor of the legalization initiative, I-502, in November 2012. It went into effect in December of that year, but lawmakers were given a year to establish the procedures and criteria necessary to implement the law.

Implementation of the law was also delayed because marijuana is still considered a narcotic by the federal government. As the government works to change drug policy, it has not shown much interest in interfering with the states' laws, and in April, US attorney general Eric Holder said he is “cautiously optimistic” about the initiatives in Washington and Colorado.

Is this different from Colorado's recreational marijuana law?

Yes, there are considerable differences between the two states' laws. One key difference is that Colorado licenses permit people to grow and sell marijuana while Washington separates the activities. Also, only people with licenses can grow marijuana in Washington, while Colorado allows residents to home grow pot.

What other states are expected to legalize recreational marijuana?

An initiative to legalize recreational marijuana in Alaska is set to appear on the state ballot in November, though it was originally to be voted on in August. The proposal would allow adults 21 and older to possess up to 1oz of marijuana and to grow as many as six cannabis plants for personal consumption, as well as set up foundations for creating commercial marijuana sales in the state.

Campaigners are focusing on getting initiatives on state ballots in the 2016 election, especially in states that have demonstrated openness to legalization, such as Nevada and California, which was the first state to legalize medicinal marijuana and has also decriminalized marijuana. In December, state attorney general Kamala Harris said that legalization would save the state millions of dollars annually.

New York’s governor Andrew Cuomo signed a medical marijuana bill into law on Monday, though he is cagey about full legalization.

Washington DC is also considering legalization, but because it isn't a state, any initiatives are up for congressional review. Mayor Vincent Gray signed a bill decriminalizing possession up to one ounce, but House Republicans have blocked funding for the bill.